The main objective is the development of new methods for the synthesis, and eventual pharmaceutical testing, of heteroaromatic nitrogen compounds starting from heteroaromatic N-oxides and related molecules. The specific aims can be divided into five broad categories: (1) extending the scope of the reaction of 1-oxido-2-pyridyl carbanions with electrophiles; (2) extending the scope of the direct acylamination reaction of heteroaromatic N-oxides and rearrangements observed in this reaction; (3) to study new intramolecular aromatic substitutions starting from N-oxides; (4) to study the O-arylation of N-oxides and the rearrangement of the products so formed, as well as of N- arylthiopyridinium salts and of N-aryliminopyridinium ylides; (5) to study the chemistry of l-oxido-2-pyridyl nitrenes and carbenes and related heterocyclic reactive intermediates. It is hoped that such studies will lead to new compounds and novel ring systems, as well as to more convenient ways of preparing known useful compounds, and that these will have valuable activity, particularly as antitumor, antiinflammatory, antibacterial, analgesic, or antihistaminic agents.